Multiplex photographic equipment support



Feb. 15, 1949.

J. T. PENNINGTON MULTIPLEX PHOTOGRAPHIC EQUIPMENT SUPPORT Filed Oct. 31, 1944 2 Shets-Shegt l o o 351: "can;

I) 6Z-@ 60 Snow trot Jhrrz, Penning/0n 61 Ho zmur I Sheets-Sheet 2 1949 J. T. PENNINGTON MULTIPLEX PHOTOGRAPHIC EQUIPMENT SUPPORT I Filed' Oct. 31, 1944 v A Q Q Q mm Patented Feb. 15, 1949 TENT orrlcs MULTIPLEX PHOTOGRAPHIC EQUIPMENT SUPPORT John T. Pennington, Alexandria, Va.

Application October 31, 1944, Serial N0. 561,247 1 Claim. (01. 33-20) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without payment to me ofany royalty thereon.v

This invention relates to stereoscopic projections and particularly an adapter for multiplex projectors. More particularly, it is directed to a device positioned intermediate a multiplex projector and its mount for selectively varying the angle of projection to accommodate oblique aerial photographs employed in the projection of stereoscopic models from which both planim-i etry, elevation and contours may be plotted.

In the past, it has been the practice to project vertical diapositives which may be stereoscopically observed and measured to obtain detail for compilation into a conventional map on paper. This required highly controlled flights for taking the vertical pictures which are necessary for acmeans which could be used satisfactorily in cone junction with the present equipment and methods for the compilation of planimetry. These investigations showed that one thousand foot interval contours could not be accurately plotted by these methods and the tedious process of computing numerous spot elevations for the interpolation of contours was impractical.

Accordingly, it is an object of this invention to provide intermediate a multiplex projector and the mounting means therefor, a device adapting vertical multiplex stereoscopic mapping equipment suitable for oblique diapositives.

Another object of this invention is to provide a device of the class herein described which will accommodate oblique diapositives without ",destroylng the translatory and rotational movement of the projectors.

A further object of this invention is to provide a device of the class herein described which will accommodate oblique diapositives of any angle up to 70.

2 A still further object of this invention is to provide a device of the class, herein described whichrwill be economical, efiicient, anddurable.

The foregoing ancl'other objects of this invention will be more apparent from reading the specification in conjunction with the drawings,

forming a part thereof, wherein:

Fig. 1 is a perspective view of the multiplex mapping equipment with the adapter interposed between the projectors and mounting means;

Fig. 2 is a perspective view ofthe multiplex projector stereoscopically-mounted with the adapter set for 60 oblique diapositives} V v Fig. 3 is a side elevation of the adapter with various details shown by dotted lines;

Fig. 4 is an end elevation of Fig. 3; Fig. 5 is a face elevation of the movable elevating bar of theadapter; I

Fig. 6 is a side elevation of Fig.5;

Fig. 7 .is a plan view of the angle Bar of the adapter;

Figfsiis a sideelevation'of the angle bar; and, Fig. 9 is a side elevation of the adapter plates. In the drawings where like members are given the same reference numeral, the multiplex mapping' equipment generally consists of a table, a projector'supporting frame 2, two or more projectors 3, a tracing table 4; and, a pair of stereoscopic spectacles, a cooling unit, and'a voltage regulator not shown; V

The surface of the table is the plane upon which the map is drawn and it is important, therefore, that this surface be a true plane since it supports .the medium upon which the map is compiled while moving "the tracing'table A there over to trace the detail from the projected stereoscopic model. Any table of sturdy COIIStI'llQ-J tion' andhaving-a'surface flat and true within one thousandthof" an inch of any linear foot is satisfactory. Leveling means should beprovided in the table structure, preferably'in the form of adjusting pin associated with the legs supportingvthe (table surface;

Thestandard projector supporting frame 2 consists essentially of two upright threaded elevating bars 6 secured to the base plates 1 Which The tracing table 4. is that part of the multiplex equipment which is used for viewing the stereoscopic model, measuring elevation in the model, and compiling the detail on the map sheet. It has a horseshoe-shaped base ll, preferably resting on adjustable quartz foot pads and three upwardly extending columns, the center one being an elevating screw [8 and the others being guide columns I9 and one of which is provided with a scale 2|. A collar on yoke 22 slides over these columns and has a threaded section operably connected with the elevating screw 18 which may be rotated by a knurled knob 23. A screen E i with a floating mark is operably connected with the yoke 22 as is a sighting device 25 with a vernier for reading the elevation r.

of the screen 24 on the scaled column I9. A clamp 26 is provided for holding the columns in parallel relationship as well as holding the screen at any desired setting. A suitable pencil holder is provided on the base I! in alignment with the screen floating mark. Suitable illuminations are provided with this device.

The above discussed equipment are standard items previously used in vertical stereoscopic model projecting and viewing. This invention relates to an adapter for the projector, which will now be discussed. Theprojector consists of fourmain parts designated generally as a body 30, condenser 3i, lamphead 32, and adapter 33. This assembly is that part of the equipment which body, condenser, and lamphead are standard items of vertical multiplex equipment adapted to oblique model utility by this'invention'.

The generally designated projector body 30 may be viewed as a small scale reproduction of the camera mounted so that it may rotate about and translate along a plurality of axes. The projector body is suspended from the supporting frame by a divided bracket 3 adapted to fit over the face bar 15. Movement along the face bar l5 and rack l2, known in the art as X movement, is obtained by the engagement of a pinion 35, on a shaft operated by a-knob36, with the rack l2. Movement in the vertical direction, known" as Z" movement, is accomplished. by a vertical bar 31 slidably mounted in the bracket 34 and movably operated by a knob 38, this vertical bar 3? being securely attached to the lower portion of this divided bracket 34. A horizontalbar 39 'isslidably and swing, respectively, is accomplished by the action of the screws 44, Qand46 acting on the levers 41 positioned by spring plungers 48. The tilt and tip motions canbe moved approximately 10 in either direction, but the swing movement is limited to a relatively small angle inthe direction opposing the spring plunger. A clamp screw 49, however, may be loosened to permit 360 swingv movement by manual operation. Thediapositive may be centered on the stage plate by'the four opposed plungers actuated-=by the thumb-screws 50.

The condenser 35 fits snugly over the projector body 30, and is held thereon by a substantially U- shaped steel spring member 5|. A spout 52 is provided for attaching a hose 53 connected to the cooler head I6 and a slot 55 is provided intermediate the light source and condensing lens to receive red or blue-green filter slides. The top of the condenser is threaded to receive and retain the lamphead 32.

The lamphead 32 is secured to the condenser by an internally threaded knurled ring. Means are provided for centering the filament of the light source longitudinally by rotating the knurled collar 51, and, transversally by two adjusting screws 58.

The adapter 33 consists of an angle bar to which is attached two side plates 6| by means of the screws 62; inserted through apertures in the side plates and engaging threaded holes in the angle bar 60. These plates 6! have an aligned central hole 53 and three spaced holes B4 arcuatelydisposed with respect to the first center hole 63. These radially spaced holes are on lines equiangular apart, namely 20, forming 20, 40 and 60 elevations. An elevating bar 'is adapted to slide between the side plates BI and be secured thereto by the boltsfit and'the nuts 6'! passed through it and'the'central holes 63":and one of the radially spaced holes 64. To accommodate the as bolts 66, retain the center of gravity of the projector and condenser at approximately the same relationship at all elevations, and also provide is correspondingly increased by employing the next'set of holes 63 in the bar 65', see Fig; 3. Thus, by keeping the center of gravity of the projector and condenser in substantiallythe same position as in normal vertical operation, no additional torques or strains are placed on the multiplex frame or bracket. The employment of the elongated bar 55, however, necessitates a clearanceangle 69 being provided in theangle bar 60.. The adapter 33, therefore, becomes the connectin link between the divided bracket mounting 34' and the projector body 30 by the screws connect ing the angle bar 60 to thehoriz'ontal bar 39and by screws connecting the-elevating bar 85 to a projector'ring studlfl through apertures 12 and threaded holes [3 provided in the appropriate members.

In operation, the projector assemblies are'set' up in bank and approximately atthe same oblique angle as the taking camera. This may beaccomplished' for any angle from 0 to since the adapter radial holeslit are spaced at 20, 40 and 60 and the projector head possesses 10 variation in either direction, the usual oblique: aerial photograph being 60. The preferred vertical distance between the table and projector is approximately 235 mm. It has been determined that the optimum plotting scale for 60 oblique models is 1:13 times the flight altitude in feet. Thus for a flight altitude of twenty thousand feet, the optimumplotting scale is 126,000. With a photograph flight control of sixty percent overlap, such a scale will permit half inch clearance between projectors; accordingly, with overlaps greater than sixty percent it is necessary to plot the obliques on a larger scale. This latter condition may be satisfactorily plotted in the area inside the principal points.

Having thus described my invention, what I claim as new and wish to secure by Letters Patent is:

An adapter for a multiplex projecting device comprising two spaced parallel plates, an angle bar, formed with an angularly cut away clearance portion, rigidly mounting said plates, a second bar pivotally mounted on the plates intermediate thereof, and angularly adjustable therebetween, the extent of said angular adjustment being increased by the cut away clearance portion of said angle bar, and means for selectively The following references are of record in the file of this patent:

UNITED STATES PATENTS 10 Number Name Date 2,079,090 Von Gruber May 4, 1937 2,138,600 Harmon Nov. 29, 1938 Erickson July 1, 1941 

